The purpose of this study is to determine whether intrauterine hCG can improve the implantation rate and clinical pregnancy rate after embryo transfer in IVF/ICSI cycle.

Patients at infertility clinic, siriraj hospital who come to start IVF/ICSI treatment cycle or endometrial preparation for embryo transfer are consiferes as eligible subjects.

On the day of embryo transfer (both fresh and frozen-thaw cycle), the subjects will be randomized to 2 groups.

1. control group: embryo transfer after intrauterine infusion with standard embryo culture media 4-7 minutes
2. study group: embryo transfer after intrauterine infusion with hCG (Pregnyl) 4-7 minutes

The patients will come back for serum beta-hCG measurement 2 weeks later after embryo transfer and other 2 weeks later for transvaginal ultrasound if beta-hCG is positive.

Inclusion Criteria:

1. infertile women aged 18-43 years
2. indicated or willing for IVF/ICSI treatment or endometrial preparation for embryo transfer

Exclusion Criteria:

1. Azoospermic male partner
2. Failure to retrieve oocyte after controlled ovarian hyperstimulation
3. No embryo retrieved for transfer
4. Endometrial preparation failure